The average fuel efficiency of the fleet of new cars and trucks rose only slightly in 2008, but the government said Friday an increase in the sales of smaller vehicles due to high gas prices could push the numbers higher.

The average fuel efficiency of the fleet of new cars and trucks rose only slightly in 2008, but the government said Friday an increase in the sales of smaller vehicles due to high gas prices could push the numbers higher.

To save money and support neighboring farms, Scott Dubbelde began mixing gasoline and cheaper, ethanol-based fuel in his cars years ago, driving first to the gasoline pump, and then to the ethanol pump.

To save money and support neighboring farms, Scott Dubbelde began mixing gasoline and cheaper, ethanol-based fuel in his cars years ago, driving first to the gasoline pump, and then to the ethanol pump.

California sued the federal government in its struggle to set the country's first greenhouse gas limits on cars, trucks and SUVs, asking the Environmental Protection Agency to review its decision to deny the state a waiver that would allow it and 16 other states to regulate emissions.

California sued the federal government in its struggle to set the country's first greenhouse gas limits on cars, trucks and SUVs, asking the Environmental Protection Agency to review its decision to deny the state a waiver that would allow it and 16 other states to regulate emissions.

Gasoline prices hit near-record levels recently, and the government says the average will stay above $3 all summer, sending motorists shopping for lower-price fuel and making them wonder if they're hurting their engines burning the cheap stuff.